1. Field of the Invention
The present invent relates generally to assessing neural survival, and more particularly, to assessing neural survival associated with an implanted electrode array.
2. Related Art
Use of a cochlear implant (CI) has become an accepted therapy for treatment of severe or profound hearing impairment. As performance of these devices has increased over time the indications for use of the cochlear implant (CI) have been relaxed to allow treatment of individuals with greater degrees of residual hearing. This trend may be expected to continue in the future.
Hearing impairment may be caused by a variety of toxins, disease processes, and developmental failures. Most etiologies of deafness result in degeneration of some auditory neurons or their peripheral processes. In most cases there is a general trend toward greater neural degeneration in the base or high-frequency end of the cochlea, and less degeneration at progressively more apical places where lower frequencies are represented. However, there is very large variability across individuals in both the extent and spatial pattern of neural degeneration. Neural survival may be “patchy” and discontinuous.
Cochlear implants function by stimulating the surviving neurons. In order to optimize the operation of an implant for a specific individual recipient, it would be of value to know how neural survival varies across differing frequency places within the cochlea. However, no reliable method currently exists for assessing such neural survival patterns.